


Even Underneath The Waves

by leveragehunters (Monkeygreen)



Category: Captain America (Movies)
Genre: Alternate Universe - Canon Divergence, Canon-Typical Violence, M/M, Merman Steve Rogers, Mythical Beings & Creatures, Non-Serum Steve Rogers/Winter Soldier Bucky Barnes | Shrinkyclinks, Nudity, Partial Mind Control, Post-Serum Steve Rogers, Protective Steve Rogers, Recovery, Sharing a Bed, Sirens, Steve Rogers is Not Captain America, Winter Soldier Bucky Barnes, but there's also sharks - because a good shark these days is hard to find, the following are for a given value of:
Language: English
Status: Completed
Published: 2017-03-30
Updated: 2017-03-30
Packaged: 2018-10-10 19:40:38
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 20,431
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/10445910
Author URL: https://archiveofourown.org/users/Monkeygreen/pseuds/leveragehunters
Summary: When the siren came to the merfolk clan in search of a temporary mate she knew she'd bear a daughter, a full-blooded siren, powerful and deadly. Instead she bore a son.It was hard to be the son of a siren, a creature of suspicion in the eyes of his father's people, and Steve soon left his father's clan to wander the oceans alone. Alone, that is, until he found a human like he'd never seen. A human dressed all in black, surrounded by blood and death. A human whose heart's desire, buried deep beneath an inhuman shell, was crying out not to kill.





	

**Author's Note:**

> So...this fic marks the one year anniversary of when I started writing again. I was gonna get super sappy here, but I figured hey, save it for the fic, you know? I _do_ want to say I wouldn't have picked up my keyboard again after ten years, and realised how much I missed it, if not for you guys. The people in this fandom are some of the kindest, sweetest, most generous I've ever encountered; thank you for being amazing. 
> 
> Title from _Find My Way Back_ by Eric Arjes, a song I discovered after this was mostly finished, but boy does it fit. This fic partially came about because Allofkorothings on Tumblr wanted to see mythological Steve.

* * *

_First you will come to the Sirens who enchant all who come near them. If anyone unwarily draws in too close and hears the singing of the Sirens, his wife and children will never welcome him home again, for they sit in a green field and warble him to death with the sweetness of their song. There is a great heap of dead men's bones lying all around, with the flesh still rotting off them. Therefore pass these Sirens by, and stop your men's ears with wax that none of them may hear; but if you like you can listen yourself, for you may get the men to bind you as you stand upright on a cross-piece half way up the mast, and they must lash the rope's ends to the mast itself, that you may have the pleasure of listening. If you beg and pray the men to unloose you, then they must bind you faster._

- _The Odyssey_ , Homer

 

The siren came alone to the merfolk clan, offering territory safe from human encroachment in exchange for what she sought: sirens were biologically female, only and always female, and she wanted a daughter.

The clan were wary, because sirens were power given voice, amoral, ruthless, deadly, but territory sheltered by a siren's song, a sanctuary where intruding humans would find only death waiting, would be valuable beyond reckoning. After a time one merman, brave and reckless, agreed to offer himself and she accepted.

Any daughter born of a siren would _be_ a siren, full-blooded and powerful.

She should have borne a daughter.

Instead she bore a son.

Her disappointment was palpable, a taste like iron on the water and the waves, but she named him Steven, touched his short stubby tail and wished him all the blessings of life, then handed him to his father before disappearing into the depths of the ocean.

Steven would never see her again.

 

* * *

 

On a rooftop in a city a man whose will belonged to HYDRA crouched in the darkness. He waited, endlessly patient, for the perfect shot. He was HYDRA's Soldier, their Asset, and he didn't move, barely breathed beyond what was necessary to sustain life.

As the sun rose and his target appeared, silhouetted against the lightening sky, a single bullet cut through the distance between them and entered the target's temple.

The man on the roof had performed well. They would be pleased. He would not be punished.

Deep, deep inside, where no one could see, no one could hear, beyond the capacity of any human to detect, a voice cried out: _please,_ _no more_.

 

* * *

 

It was hard to be a siren's son.

The burning sword of his mother's power was tempered by his father's blood, but it was still part of him. The merfolk of his father's clan knew it was there. For all that he never touched it, his voice held the potential of a siren's song and he was a creature of suspicion.

Son of a siren.

When Steve was grown, he left, preferring a mostly solitary existence to the poorly-hidden wariness of his father's people.

He fell into following the sharks as they migrated through the world's oceans, herding them away from human nets and human activities. Steve liked sharks. They were affectionate in their own way, and he hated seeing them killed because humans were too stupid to stay where they belonged.

The first time he unleashed his power was the day the boat full of humans, who'd been teasing the sharks with food, stabbed something into the fin of his favourite shark and _cheered_. They'd been floating around the sharks for days, but this was the first time they'd hurt one of them.

Except the shark they'd stabbed didn't seem bothered by the black _something_ that was stuck on his fin, and Steve didn't understand what the humans were doing. They showed no signs of leaving, so when the sun set and the humans had dropped their anchor, were sitting on the deck of their boat, he tapped into his mother's power.

Cautiously, carefully, warily.

It wasn't a song, not yet, just a vibrating hum, in his chest, in the back of his throat, well below the capacity of human beings to hear, to even notice, and it told him their hearts' desires.

What flowed back shocked him to silence. It was love, love for the sharks, love for the ocean, formless and shapeless, all shot through with the desire to _know_ , to understand, to learn everything.

They wouldn't hurt the sharks. Of anything he'd ever been sure of he was sure of that and, for the first time in his life, Steve tipped back his head, barely aware of what he was doing, and let his siren's song flow free, a song that wound golden tendrils inside the four humans and promised them everything their hearts desired.

It took Steve only seconds to realise what he was doing. He snapped his mouth shut and dove beneath the surface while the humans pressed against the rails of their boat, blinking at each other as they rose from their stupor. "What the hell?" the small woman asked.

None of the others replied, just looked at each other in mutual confusion.

Steve, guilty at what he'd almost done, swam deep down to the ocean bed. While he was there he reseated their anchor to hold better and swore to be more careful. He hadn't realised how _tempting_ it would be.

He stayed with them, though. They were interesting, these humans who loved the ocean, who loved sharks, who wanted to _know_. He helped them when he figured out what they wanted, herding the sharks close to them.

"It's like they're wantin' us to study 'em," the tall woman laughed as she did something to a shark's fin.

"You say that as a joke but this is the second time Feargal's been up to the boat today. And look at him, he's just hovering there."

Steve, listening from a safe distance under the belly of a large shark, who was ignoring him with a studied kind of disdain, smiled and went to round up more sharks.

As he listened to them talk, while they worked and while they relaxed, he was learning from them. Learning about human things and human ways of being. How they interacted with each other, how they felt about each other, that the tall woman and the small woman were, he was quite sure, hopelessly in love. Which made him a little sad since neither seemed willing to tell the other.

 

* * *

 

In a secret room, erased from the records of the world, the man whose will belonged to HYDRA was confused. It wasn't...something was wrong.

"I have to go. I have to get to..." he mumbled, barely audible.

A tall man with soulless blue eyes stared down at him. "What's wrong with him?"

"It's nothing serious, sir. He's just past due for a wipe."

"And _why_ is he past due for a wipe?"

"Uh," there was a long silence, the sort in which the holder of the silence knows there's no good answer he can give, "operational requirements have necessitated an alteration to the standard schedule."

"I have to go." He looked up at the man with the pale blue eyes. "I have to get to..."

"Get to where?"

"I don't know." He looked at the ground.

"There's nowhere you have to get to. There's nowhere to go. This is where you belong. This is where you've always been. This is where you'll always be. Understand?"

He moved his head, a slow shake side-to-side.

The blue-eyed man was angry. He'd failed. But there was somewhere…

"Wipe him. Now. And don't let it get this bad again."

"Yes, sir."

 

* * *

 

Watching the humans on the boat, watching them on their two legs, made Steve want to try taking their shape. It was the gift of his father's people but he'd never done it before.

He'd known it would be different, to have legs instead of a tail, to lose his gills and his scales.

He wasn't expecting everything else he'd lose. His father had warned him, warned him that the land demanded a price to walk on its surface, that the ocean exacted a toll to leave her, but it hadn't prepared him.

The first time he tried it he threw himself back in the water and wrapped his arms around his tail, shivering.

Gradually, he grew to accept it. He learned to walk on land, learned to enjoy the feel of air on his skin, to feel sunlight unfiltered by the water. To curl his toes in the sand. To _have_ toes to curl.

But not often and only where it was safe. The water was his home, it was where he was powerful, and it was where he mostly stayed.

 

* * *

 

They dropped the man whose will belonged to HYDRA in the water to wait and he waited.

When it was dark, only the moon and the stars to light the way, he swam to the yacht and climbed on board.

This was unusual. Normally he was sent to kill one or two people. This was an entire boatful. But he would perform well. They would be pleased. He would not be punished.

As they began to die, as someone hit the emergency lights and cast the deck in lurid red, the voice that was buried deep inside, beyond the capacity of any human to detect, cried out: _no more killing_. _I don't want to kill anymore._  

 

***   *   ***

 

The scent of blood woke Steve, creeping into his dreams as he slept with his tail curled around a rocky outcrop deep on the seabed. The sounds of sharks feeding, thrashing, arguing, fighting over their meal, drew him up towards the surface.

He saw the bottom of a boat cutting through the water's surface, sharks bumping into its sides as they tore into human bodies. Blood coloured the water a sickly red.

He eased closer, only his head above water, cutting through the ocean like the sharks' fins, barely a ripple to show his passing. There were lights on the boat, illuminating the carnage. A shark bumped into him and Steve shoved it away, eyes fixed on the man standing on the deck.

From what Steve could see he was the only one alive and Steve had never seen anything like him. The humans he'd known, they'd always been moving, talking, laughing. This man, the way he was standing he looked like the figurehead of a sunken ship, so still he could have been carved from wood. Or steel. Or stone.

He was black from head to toe, only a slash of pale skin visible on his face, one arm gleaming like silver scales.

There was a gun in his hand, a knife in the other, and he was still. So still.

Cautiously, Steve swam closer.

The man was spattered with blood. This close Steve could see he wasn't still. Fine tremors, barely visible, were running through him.

He was standing in the midst of death he'd created and he was shaking.

Closer, close enough to put his hands on the sleek hull of the boat, and Steve could feel...something. Something plucking at him. A heart's desire so strong it was reaching into the deepest part of him and he felt his power stir.

_Son of a siren._

It was impossible to resist, his power called like the sharks to water teeming with blood and bodies; he reached out, delicately reading it, and it _slammed_ into him.

 _No more killing. Please, no more killing. Don't make me kill._ It pulsed out of the man, blood from a mortal wound, but it was distant, like screams from inside a sealed cave. The man was standing surrounded by bodies he'd made, expressionless, wrapped in black, armed and deadly, but his heart's desire was screaming at Steve: _don't make me kill again._

Steve ached for him. He didn't understand what was happening, didn't understand how someone could be a killer who didn't want to kill, but it fired anger in his heart. A killer who didn't want to kill was someone who'd had no choice.

Anyone whose desire not to kill was so strong, so pure, would not willingly have created so many dead.

There was no thought, no decision made, Steve simply rose higher in the water, tipped back his head, and began to sing. A siren's song, a promise of everything the man desired: _no more killing, you'll never have to kill again_.

The song wound through the man, reached into him, seductive and warm. _Follow the song, follow me, come with me, come to me, and your days of killing will be over._

 

***   *   ***

 

The Soldier wasn't precisely human. That was the point. He was designed to be an obedient machine, a compliant shell whose will was not his own. Programmed to do whatever was needed, but above all to kill. The perfect HYDRA asset, to be stored against future need when his missions were done.

But the nature of a shell is that it's got something inside it. And much as HYDRA hated it, the something their shell contained was the man who'd once been James Buchanan Barnes.

They'd tried to kill him, to wipe him out completely and leave only their obedient Soldier, their compliant Asset. They'd failed, vestiges of the man resurfacing again and again.

In the face of that failure they wrapped him in layer after layer of torture and brainwashing and drugs, wiping the surface clean again and again, but he was still there, buried deep.

Still human.

Nothing human could resist a siren's song.

There was no one to stop up the Soldier's ears with wax. No one to lash him to the mast.

The siren's song wove its way past the Soldier, eased through the cracks, and found the man who'd been James Buchanan Barnes. It wrapped him in inescapable golden threads, whispering sweet words of promise, and he followed.

He had no choice.

The song was golden and warm and he was helpless before it as it promised he'd never have to kill again.

It didn't hurt. He wasn't afraid.

Floating on the song, he drifted, stumbled, and didn't flinch as black water closed over his head.

 

  ***   *   ***

 

Steve's song hit a barrier, a shell, as if the man's mind had been encased in armour, but Steve dug deeper and it cracked, fell away, and Steve found the man inside. He called to him, lured him out with the promise of his heart's desire.

The man's head snapped around and his eyes were wide. Slowly he started walking towards the edge of the boat, sped up, tripped over a body but caught himself with an unconscious grace that kept him from falling.

Enthralled by Steve's song he reached the boat's edge and stepped over the side, sinking like a stone when he hit the water.

A siren's song was meant to lead the humans it lured to death and destruction. A siren's song was meant to be a lie.

Not a truth.

Not a promise.

But Steve _wasn't_ a siren. He was only a siren's son.

Steve dove after the man, wrapped his hands in the straps of his strange clothing, and dragged him to the surface. He stripped the water-logged coverings from the man's face and he breathed deep, limp in Steve's hold, head lolling against Steve's shoulder, and Steve kept up a gentle, low-voiced croon as he stole the man away.

 

  ***   *   ***

 

He didn't understand what was happening. There were strong arms around him, cool water lapping against his chin but he wasn't cold; the body behind him was hot.

He didn't understand.

He'd been nothing. He'd been gone. He'd been the Soldier and then there'd been a song, sweet and golden, rolling through him like honey, promising him everything. It had found him deep down in the dark and pulled him free. Then he'd only been the song, the song and the promise and the world had been gone.

He was moving through the water, through the ocean, salt on his lips, faster than he could swim, and he didn't understand. They'd sent him to wipe out the boat, to kill everyone. He'd done the job. They'd told him to wait when it was done, that he'd be collected.

But then there'd been the song.

Whatever had him was still singing, a low croon in his ear, but it wasn't the same. It wasn't reaching inside of him, seductive and promising, blocking out the world.

Had he been captured? Maybe he should fight. His arms were free, his hands were empty but he could reach his knives. He should fight, but his mind was hazy. He tensed and the arms around him tightened. They were too strong, stronger than _him_. They felt like restraints. He thrashed, trying to get away, and a deep voice said soothingly, "You're safe. I promise, you're safe." The voice sounded like the song. "I can't let you go or you'll drown." But the arms loosened, gentled, as they stilled in the water. He stopped fighting and hung limp. "My name's Steve. I'm not going to hurt you."

There was something wrong with Steve, his body felt _wrong_. He wanted to turn and look, but he was being held securely, his back against Steve's chest, and he couldn't see. "Do you," Steve hesitated, "do you want me to take you back?"

He didn't understand what was happening, but there was something missing from his mind, like a door had been unlocked. "Don't take me back."

"I won't." It sounded like the song, like a promise, and he didn't understand but he believed.

 

  ***   *   ***

 

It made Steve feel a little less like he was stealing the man. Steve's intentions had been good, but what had made sense, what had seemed right, in the flush of anger-shading-to-rage at the strength of the man's desire seemed less sensible now.

He didn't regret it. All he'd been thinking of was getting the man _away_ , but he didn't regret it. He couldn't, not after: _Don't take me back._ He was just grateful he had somewhere to take the man. It wasn't too far away. Not by Steve's standards, anyway. He'd take the man there and figure out what to do after that.

The sun was rising, casting the sky in crimson, by the time the island came into view.

"I have to take you underwater. Can you hold your breath?"

The man nodded, feeling limp and exhausted in Steve's arms, and Steve said, "Now," and ducked them both under, swimming fast through the maze of rocky tunnels that led into his cave. He broke the surface of the water into light and fresh air, holes in the rock above letting in both.

This was where he came when he wanted to walk on two legs, when he wanted to feel the sand and the sun. A secure place where he could leave the ocean. There were a few things here the man could use; not many, but it was better than the nothing that would have existed anywhere else and he'd be _safe_.

 

  ***   *   ***

 

They rose up from under the water into a cave, rocky ceiling stretching high above them, sunlight lancing down like spears through holes in the roof, water lapping at the sheltered shore. It was big, stretching back into darkened shadows he couldn't make out.

As Steve swam them closer to the shore his boots hit solid ground. He could stand, take his own weight, but Steve didn't let go. "Please don't be scared when you see me."

He was exhausted, but he went cold at the words, a hit of adrenaline jolting him awake. He had to fight not to fight. Not to lash out and try and throw Steve's arms off. Steve was obviously waiting for an answer, but he didn't have one to give.

Finally Steve let go and he whirled, shoulder-deep water swirling around him. Steve was big, broad shouldered and shirtless, square-jawed, heavily muscled, damp blond hair plastered against his head, bright blue eyes watching him carefully.

His eyes moved lower and stopped. Iridescent scales coated Steve's stomach, leading down to a... "What are you?"

"Probably easiest if you think of me as a merman."

"You have a tail." It began at his hips where he should have legs, was long and thick, dark blue with lighter-coloured fins trailing along its length.

"I do."

He reached down through the water, wanting to touch it, to make sure it was real, and Steve twitched it out of the way. "Please don't," Steve said gently and he dragged his eyes back to his face. There were three pink slits on each side of his neck. _Gills_ , his mind supplied. They must be gills.

He fought down the urge to giggle hysterically, afraid if he started he wouldn't stop. Maybe he was dead. Except if he was dead there'd be demons and pitchforks and hellfire, not warm water lapping gently against his chest and a merman with a soft, strong voice.

"There's blankets and some fresh water. No clothes, but if you can give me a few hours I'll see what I can find. You'll be safe here."

 _Safe._ He didn't know what to do with that; it had no meaning, no frame of reference.

"Do you have a name?"

Did he? He must have a name. Not the Asset. Not the Soldier. Those weren't _names._ There was an unlocked door behind his eyes and he pushed it open. His mind was buzzing, filled with bees. They made a sound. _Bucky_.

"I was called Bucky." It was confusion and wonder and Steve reached out like he was going to touch him, then pulled his hand away. He didn't know if he was grateful or not.

"Okay, Bucky. Do you think you can get out of the water?"

Bucky nodded.

"Will you be all right if I leave you? I won't be long, no more than a few hours." Bucky shrugged. A look of concern passed over Steve's face. "I'll be back as fast as I can. Go on, now, out of the water."

Mind empty with an order to follow, Bucky turned and slogged his way up the shore. It was hard, his uniform weighed down by the water that was streaming off of him, his boots full and sloshing with every step, but he made his way across the sand, sat with his back against the rocky wall and waited.

 

***   *   ***

 

Steve didn't want to leave him, but Bucky needed human things. Food. Clothes. Steve didn't want him to have to walk around naked. That was important to humans, and he'd need to get out of his wet clothes.

He poured on the speed and ate up the distance. The island was far away from any routes that humans used, far away from anything humans found interesting; that was why he'd chosen it all those years ago, but right now he _needed_ humans. Preferably humans with big fancy boats that Steve knew from experience wouldn't miss a few things.

It took him a few hours to find what he was looking for, but he got lucky, the boat ridiculously fancy, its people gone, the little boats missing. He traded tail for legs and slipped aboard, found clothes that should fit Bucky, slipped into the galley and filled a net bag with food that would survive the trip back, sealed the clothes into waterproof bags, and dove soundlessly into the water.

The return trip was shorter, Steve swimming faster, but he'd still been gone longer than he'd wanted. He could see Bucky sitting against the wall.

"Bucky?" he called from the water. There was no response. He called again and Bucky didn't move. His eyes didn't shift. He was staring into the distance, didn't seem to realise Steve was there.

Steve hauled the bag out of the water, tossed it in Bucky's direction, and considered Bucky. He could change, could walk up onto the sand, but he didn't want to do that, not if it could be avoided.

Softly at first, letting his voice deepen, he began to sing. Not a siren's song, just a song, a lullaby his father used to sing to him when he couldn’t sleep. It echoed through the cave, bouncing off the walls, swirling through the air.

Bucky twitched, stirred, sighed and blinked like a man coming out of the dark into bright sunlight.

Steve let the song fade.

Bucky focused on Steve and surprise passed over his face. "You came back."

"Of course."

"I didn't think you'd come back."

Steve wasn't sure what to say, but it made his heart ache. "I wouldn't leave you here," he said quietly. "I've got clothes for you. You should get out of those wet things."

Bucky nodded and stood, started stripping with no apparent concerns. Steve averted his eyes, knowing humans usually cared about being naked in front of strangers, but he couldn't help looking back when the light reflected off what Steve realised was a metal arm. Couldn't help staring at the scars. They made him want to shudder. The metal looked like it had been _driven_ into his body, masses of scars bubbling around the edges. He couldn't imagine the pain.

"Did you drink some water?" he asked when Bucky was dressed in loose cotton pants and a grey t-shirt.

"No."

"You need to drink some. There's bottles along the back wall and the things in the bag are for you. Are you hungry?"

It took a long time for Bucky to say, "I think so," and he didn't sound certain.

"I'll go and catch you some fish. Do you think you can start a fire?" Steve ate his fish raw, but he didn't think Bucky should. "There's wood and matches, and if you set it up under one of the holes the smoke vents into the sky." _Fire_ was one of the human things he'd learned to love: the heat of it, the light and sound, the changing colours, the smoky scent. He made sure to restock his cave with firewood and matches whenever he left it.

"Yes." 

"Okay, you do that. I'll go get you some fish."

Steve turned and dove back down into the water, swimming out into the ocean, following the curve of the island to the sheltered cove, teeming with fish.

He was tired from the long, fast journey, but not so tired he couldn't dart among them, plucking them up as they tried to escape. A thumb in a gill and a quick flick killed them instantly and he ate his fill before catching three to bring back to Bucky. They were good sized, should be enough to feed him, but he could come and get more if he was still hungry.

When he popped out of the water in the cave a fire was burning, right under one of the holes in the cave roof. Bucky looked up and Steve raised the fish. 

Soon there were three fish spitted on a long stick, the guts tossed back into the water where the tide would carry them out, and Steve had discovered there were a lot of knives in the pile of black that Bucky had been wearing.

He stretched out in the water, tail curling and uncurling in the rippling waves, chin resting on his hand, elbows propped in the sand, watching the fire and singing softly as Bucky ate his fish. There was no power in his song, but Bucky seemed to relax, seemed to find a sort of comfort in it.

Steve didn't know what he was going to do with Bucky, but he had food, he had water, and he was warm and dry. That was enough for now. Hopefully tomorrow would look after itself.

 

* * *

 

The next few days passed in much the same way. Bucky spent most of it sleeping. When he woke with some prodding from Steve he'd eat and drink. The water wasn't going to hold out much longer, but Steve could take the bottles and refill them from the spring on the island. There wasn't going to be anything to eat but fish, soon, but Steve could go and hopefully find more humans to raid.

Steve rested in the shallows, alert for any change in Bucky.

When Bucky was awake, he seemed reluctant to talk. When he was sleeping, it wasn't peaceful. Steve didn't think it was restful.

Awake, Bucky seemed to get lost in himself, staring into the distance. When that happened, Steve would sing, soft and low, not a siren's song, just a song, lullabies, songs of his father's people, and eventually he'd come back. Move to sit close to the water's edge, watching Steve like Steve was a mystery he could never understand.

 

* * *

 

"Bucky?"

Bucky looked up from staring at his knees, which were covered in soft, cream-coloured cloth. His eyes met brilliant blue ones. Steve. He looked worried.

"I need to go and find you more food. That means I need to leave you."

Bucky nodded.

"Will you be okay?"

He shrugged, because he wasn't sure what that meant. He wasn't sure he was okay now. He was trapped in a cave and a creature that couldn't exist brought him fish and sang to him and looked at him with worried eyes.

"I'll be back as soon as I can." Steve hesitated, like he wanted to say something or do something, but in the end he turned, long scaled tail breaking the surface of the water, feathery fins sending a shimmer of sparkling droplets cascading in a wave, and dove down into the depths of the water.

The circles of light from the holes in the cave's roof crept across the sand. Bucky grew thirsty but he didn't drink.

Steve still didn't return.

Maybe Steve had never existed. Maybe Bucky had invented him. Maybe he'd always been alone in this cave.

Maybe this was a test and any moment they'd arrive and take him back, put him in the chair and wipe the memories of being Bucky. That’s what they did when he malfunctioned.

Maybe he wasn't here at all.

 

* * *

 

It had taken way too long to find an unattended boat that he could creep aboard and help himself to food and more clothes for Bucky. After a moment's thought, he grabbed some other things: soap, a toothbrush, a comb. Things that Bucky might need, that might help him.

Two thirds of the day was gone and it was pushing into late afternoon when he swam back into the cave. "Bucky, I'm back," he called.

Bucky was sitting where he'd left him, hands on his knees, legs folded. Still and silent.

"Bucky?"

No response.

He sang, a gentle lullaby, but Bucky didn't react. Didn't so much as twitch. He tried a battle song, something designed to stir the blood and rouse the mind, and there was still no reaction.

Steve could call him with a siren's song, could lure him to the water's edge, but he wouldn't do that. Not again. Not when there was another choice: he could leave the water.

Still, he hesitated.

It was one thing to sneak aboard the boats of absent and inattentive humans, where he could slip back over the side and escape, surrounded by the deep ocean on all sides where they could never follow. It was another to trade tail for legs and walk up onto the sand here in the cave with Bucky. To show himself to Bucky.

He studied Bucky, taking in the vacant gaze, the fact that he didn't seem to have moved at all while Steve had been gone, and chewed at his bottom lip.

He was going to have to.

Steve concentrated, felt his true self melt away.

Like his father's people Steve could walk on land, trade tail for legs, but it came with a price. The land didn't welcome him, the ocean hated him for leaving, and when he rose to his feet he was small. Thin and bony. Weak. The jealous ocean kept her strength when her children abandoned her.

When he was standing firmly on dry sand he rummaged around in the net bag to pull out a shirt, unsealed it from the waterproof bag and shook it out. It was sized for Bucky, far too large for him, and it hung to mid-thigh, clinging to his wet skin.

He didn't care about being naked, but he knew humans did.

Steve made his way across the sand to crouch near Bucky and called his name. When there was no response he reached to touch him, but before he could make contact Bucky's head snapped up and he threw himself away, scrambling backwards until he hit the wall.

He was breathing hard, breathing fast, and his eyes were dark and wild. Fixed on Steve.

Of course Bucky wouldn't recognise him. Steve hummed, low and soothing, softly sang the lullaby, waiting patiently.

Gradually Bucky's eyes cleared, calmed. He settled. Stared, confused. "Steve?"

"It's me, Bucky. I know I look different, but it's still me."

Bucky's eyes travelled over him slowly, like he was mapping him from head to toe. "You're so little."

"I'm aware," Steve said, a touch dryly.

"You're big when you're in the water."

"That's because I belong in the water. It's my home. I can walk on the land, but I don't belong here. The land doesn't let me forget it."

Bucky stared fixedly at one of Steve's bony wrists, his own fingers flexing. "It would be so easy to hurt you when you're like this."

Steve eyed him carefully, very aware of Bucky's size, his strength, of his lack of both, ready to move if he needed to, and quietly asked, "Is that a threat?"

Bucky turned his eyes away. "No."

For a long moment, Steve studied him, but there was nothing he could see that made him doubt Bucky's word. "Okay." He stood and went to fetch the net bag.

"Steve?"

Steve crouched in front of Bucky, started pulling things out of the bag, laying them on the sand. "Yes?"

"Are you real?"

Startled, Steve looked at him. "I'm real."

"Are you sure?"

"I'm sure. Here." He offered his hand, wiggled his fingers until Bucky looked at it. Tentatively, Bucky touched it, poked it, pressed two fingers over the veins visible through his pale skin to feel his pulse.

"You had a tail before, did I imagine that?"

"No, Bucky, you didn't imagine it. When I'm in the water I have a tail. I have gills." 

"And you're big."

"And I'm big."

"Can I ask something else?"

"Of course."

Bucky seemed to be looking for the right words and Steve waited patiently. "Will I ever be allowed to leave the cave?" he finally asked, eyes on his fingers pressed over Steve's pulse.

It was like ice in his veins. "You can leave whenever you want." But of course he _couldn't_. Not without Steve. "I'll take you wherever you want. Just tell me where you want to go. When you want to go." He couldn’t keep the distress out of his voice. "I'm sorry. I should have told you that. I should have made sure you knew that."

"I wasn't sure."

Steve felt sick. Bucky had thought he was _trapped_. This place that was _safety_ to Steve, safe for him to walk on two legs, was a trap to Bucky. "It's going to be dark in a few hours, we shouldn't leave now, but if there's somewhere you want me to take you, we can go tomorrow."

"There's nowhere to go," Bucky said. "I just needed to know if I was your prisoner."

"No. No, Bucky. You're not my prisoner."

"I wasn't sure why else you would have taken me." He frowned, eyes flicking back and forth. "I've been taken prisoner before, but," he looked around the cave, gaze pausing on the beams of sunlight, then it settled back on Steve, "but this is different."

Steve gently pulled his hand from under Bucky's fingers, wishing he was in the water for this, but he shuffled back a step and sat in the sand. "I took you because you didn't want to kill."

Bucky looked at him blankly.

"My father was a merman, that's why I can walk on land, but my mother," he wasn't sure Bucky would understand, in any sense of the word, but he needed to tell him, Bucky needed to know what had happened, what Steve truly was, "my mother was a siren. I sung to you, I called you to me with my song, and you had to answer."

Bucky's blank look gave way to confusion.

"That's what a siren does. A true siren can lure an entire shipload of humans. I'm only a siren's son. My power is...much less. But if a human has a heart's desire they can't resist my song, and every human has a heart's desire."

"I don't."

"Yes you do, Bucky. You were practically screaming it when I found you." Into the deep silence that followed, Steve whispered, "You wanted to stop killing. You didn't want them to make you kill again. It was so strong, so pure. You were surrounded by the dead and all you wanted was not to kill. I couldn’t leave you there, so I sang you your heart's desire. I called you and I caught you and you came to me in the water."

"I remember." It was slow, Bucky's eyes fixed on his face. "I remember the song. It was golden and warm and it didn't hurt." His eyes sharpened. "You said you'd take me back."

"Only if you wanted me to. You said no. You said, don't take me back. So I didn't. I stole you away."

"And brought me here."

"I thought the cave would be safe. It's where I come to be safe, but," Steve thought about humans and sunlight and Bucky, "but there's the whole island. Tomorrow I can take you there. It would probably be better for you." 

"We can leave the cave?"

"Yes, Bucky. We can leave the cave. I took you, and maybe that was wrong, but you're not a prisoner. I promise."

There was a long moment of silence and Bucky dragged one finger through the sand. "I really had a heart's desire? And it was not killing?"

"You really did. You still do, have a heart's desire, I mean. Humans always do. I don't know what it is, I'd have to read you again to know and I won't do that to you, but I don't think they change much."

Bucky didn't reply, just kept sweeping his fingers through the sand, watching the patterns they made, but the corner of his mouth pulled up the tiniest amount. It was the first thing even approaching a smile Steve had seen and it filled him with hope. 

 

* * *

 

Steve returned to the water for the night, tension easing as his proper shape formed around him. For all that he believed Bucky when he'd said his words weren't a threat he didn't like feeling vulnerable and on land, in Bucky's presence, he couldn't shake the feeling.

The next day they moved to the island proper. Bucky's eyes were uncertain when Steve left him alone, swimming out and away, like he'd never see Steve again. "I'm coming back, Bucky, and I'll see you real soon."

It didn't take long before Steve was grinning down at him through one of the holes in the roof of the cave and Bucky tentatively smiled back. He bundled everything into a blanket and Steve lowered the net bag and between them they managed to sort it out, but Steve missed his strength something fierce hauling things up through the hole.

When he went back for Bucky, Bucky wrapped his arms around Steve's shoulders, face pressed against Steve's shoulder blade while he held his breath, and the metal arm felt hard and strange against his skin.

When Bucky stepped out of the water onto the beach, he tipped his head back into the sun and closed his eyes and Steve knew this was already better.

 

* * *

 

The island was a revelation. It wasn't very big, only took maybe half an hour to walk across, but it was bright and green, the few birds scolded him fearlessly from the trees. It was tall on one side, the rock ceiling of the cave he'd been trapped in— _not trapped, you weren't trapped, Steve didn't mean to trap you_ —the start of a rock slope leading up to a high hill. The hill was home to another cave, deep enough to be a decent shelter.

Bucky spent the first day learning the entire island. The second, he carefully moved rocks and pulled down a few young bendy trees, pulled down vines and branches, and made a door for the cave. He made a pallet to sleep on out of one of the blankets wrapped around grasses and leaves and anything dry and soft he could gather. Steve came up out of the ocean to help. He wasn't strong, he was so small, but he had clever fingers and a sharp mind.

Bucky couldn't help noticing that on land Steve preferred to keep a careful distance between them, but he still came out of the ocean when Bucky needed him. He came out of the ocean to bring Bucky fish. He came out of the ocean to sit by the fire and stare into the flames with Bucky.

Some days he disappeared for long hours, for the entire day; never without letting Bucky know he was going, but each time Bucky was sure this would be the time he didn't come back.

But Steve always came back. Gradually Bucky stopped being afraid he wouldn’t.

Whenever he returned he had something for Bucky. Candles and matches in a waterproof bag. Soap. Clothes. A razor. Food that wasn't fish: sweet things and savoury things and fruit. Salt and spices to make the fish better. Bucky knew Steve must be stealing them but that didn't even register as a problem.

When you'd killed as many people as he had _stealing_ was kind of a non-event.

The candles and matches were especially welcome. When he woke in the night in the dark of his shelter, nightmares clawing at his gut, being able to make a light was a gift.

Some nights, most nights, after a nightmare he'd stare at the flickering candlelight for a few minutes then blow it out and make his way down to the cove where he knew Steve would be sleeping. Sometimes Steve would rest quietly in the shallows while Bucky sat on the beach, waves washing over his feet; sometimes Bucky would strip down and slip into the water with him to let the waves lap against his chest.

Steve never asked why he was awake. Steve just stayed with him, a warm presence, strong and reassuring.

Sometimes they'd swim in the night-black water under the star-studded sky.

Bucky had known how to swim, even if he didn't remember learning, but then there were a lot of skills his body knew that his mind was surprised by. He was just grateful his arm was waterproof. He tried not to think about the fluids it had probably been designed to keep out.

His swimming had been, by Steve's standards, not good. But Steve had never hurt him, never laughed at him or threatened him. Steve had patiently helped him find the best shape for his body, the best way to move through the water with his metal arm. Steve had taken him out into the deep ocean where the waves were barely present, the ocean floor was a distant thought, and the island couldn't be seen even with his enhanced sight and Bucky had never once worried that Steve would leave him there.

When he grew tired enough to sleep, too tired to swim anymore if they'd been swimming, Steve would watch as he made his way back to his shelter and, safe under that gaze, Bucky would be able to rest.

Some days he thought about saying to Steve: take me somewhere else, take me off this island. And then he thought: why? Why should he go anywhere else? He was safe here, or as safe as he'd be anywhere else. He had food and water and shelter. And he had Steve who he was coming to believe, deep down inside, wouldn't hurt him. It was such a strange thought he spent a few days turning it around. Steve wouldn't hurt him. He couldn’t remember the last time he'd been with someone who wouldn’t hurt him.

But then he couldn’t remember much of anything, so that wasn't a surprise.

Each day that passed he felt like the door that had opened, the one he'd found _Bucky_ waiting behind, was maybe creeping open a little bit further. The bees were buzzing in his brain and he couldn’t understand them yet, but he thought they were trying to talk to him.

There were days he lost. Days he'd look up and find Steve, small and slight, crouching in front of him, looking at him with concern, and he knew too much time must have passed, Steve worried enough to have come up out of the ocean.

But he thought those days were getting less frequent. It was hard to keep track of the days at all, much less keep track of good days and bad days, especially when he didn't really know what those meant.

They were hard to keep track of, too, because more and more Steve was coming up out of the ocean when Bucky _didn't_ need him. Like he was getting more comfortable being around Bucky when he was small. Bucky was pretty sure that meant maybe Steve was starting to trust him, which might be stupid and might be crazy when Bucky didn't think he trusted himself, but it might also be why those bad days were getting fewer.

 

* * *

 

Bucky was floating on his back in the sun-warmed cove, metal arm folded across his chest, right arm stretched out, fingers spread wide, eyes closed.

For all that Steve seemed to be getting more comfortable on land Bucky knew he was happiest in the water, so that was where they spent most of their time. Bucky was getting pretty comfortable there, too. With everything Steve had shown him, even with the weight of his arm he could eel through the water almost like he'd been born in it.

Not as fast as Steve, never as fast as Steve—and he wasn't sure he'd ever get tired of watching Steve move, lithe and powerful, his long tail flexing and curling, trailing fins waving like banners—but he was smooth enough, fast enough, they could play tag. No, he'd never be as fast, but Bucky had _tactics_ on his side, could think six moves ahead, could use the weight of his arm as a rudder, and had no compunctions about pulling himself out of the water to race over the rocks and cannonball back in to smack Steve on the shoulder when he least expected it.

It made Steve laugh, made Bucky grin smugly, whenever Bucky got him.

Steve was swimming lazy circles around him, and Bucky wasn't sure if he was buying the whole dozing thing or not, but he was tracking Steve, ready to pounce, counting down in his head. _Now._ His eyes popped open, he lunged forward, but Steve flipped under the water, swimming beneath him, and his fingers brushed Steve's tail.

Bucky jerked his hand away. "Sorry," he said as Steve came up on the other side of him. 

"Why?"

"You don't want me to touch your tail." He remembered the first time he'd tried, and he'd always been careful not to touch it since.

"I didn't. I didn't know you." Steve looked at him speculatively and curled his tail around so the feathery fins on the end brushed Bucky's fingers. "Do you still want to?" He did, Bucky realised, and he nodded. "Go ahead," Steve said with a gentle smile.

Carefully, glancing at Steve to make sure he wasn't going to change his mind, he ran the tips of his fingers down the curve of Steve's tail. It was smooth, the scales only slightly pebbly, and he flattened his palm against it, feeling the muscles move as Steve flexed it under his hand. "It's beautiful," he murmured, not meaning to say it out loud, and looked up to see Steve's cheeks were pink.

"It's just my tail. It's nothing special."

Bucky shook his head, but didn't bother protesting, because he knew Steve wouldn’t listen. It was beautiful the way Steve was beautiful and he froze for a second at the thought. _Steve is beautiful._

"You okay? It's not too strange?"

"No, it's part of you, it's not strange." Bucky ran his hand all the way down Steve's tail, gentle with the delicate fins at the end, and smiled fondly as they curled around his fingers. "Thanks."

"You're welcome."

Later, when the sun was starting to sink below the horizon and Bucky was starting to tire, he tried to cover a yawn while he reluctantly eyed the shore. He should get out, but he didn't want to. Didn't really want to leave the water. Didn't really want to leave Steve.

Steve moved up next to him. "Stop swimming for a second?" Bucky obeyed, going still, but before he could sink below the waves Steve's tail wrapped around his legs. It was strong, cool, a contrast to the heat of Steve's chest. He felt Steve take his weight, Steve's arms spread wide, moving easily in the water, enough strength in them to keep them both afloat. "Okay?" he asked, sounding a little unsure, and his tail twitched, like it too was uncertain of its welcome.

It was strange, and maybe it should have felt like restraints, because there was no way he could free himself, but all he felt was supported. Safe. He didn't need to be strong enough to escape, because if he said 'not okay' he knew Steve would release him. "Yeah, but you've gotta wake me up if I fall asleep," he said, reaching down to pat Steve's tail. Steve's soft laugh filled the air around him and he relaxed, lying quietly in its embrace, knowing Steve would never let him drown.

 

* * *

 

The weather on the island was usually mild, but Steve could feel the storm coming. The ocean always knew and Steve could feel it in the wind and the waves. By the time the clouds had piled high and black in the sky, Bucky was tucked into the shelter. It was strong and dry and he'd promised Steve he'd be fine on his own.

Steve was floating on his back in the cove, watching the swirl of the clouds, keeping himself in place with strong sweeps of his tail. If it got bad enough he'd go to the sea bed but for now he wanted to watch the storm, the lightning, the patterns of wind.

And from up here he could see Bucky's shelter.

The storm was stronger, angrier, than he'd been expecting, the wind driving the waves into a swelling froth. He was barely keeping himself above the surface, but there was joy in letting the storm-tossed sea have him. It couldn't hurt him, this was where he belonged, and he tipped his head back and laughed as a wave threw him into the air and crashed over him, spiralled him back down into the seafoam. As he broke the surface, wiping water out of his eyes, he froze and the waves tried to drag him under.

Bucky was standing in the storm. Motionless.

Steve didn't hesitate before he was swimming for the beach, reaching for legs when he hit the sand, running up the slope. "Bucky! Get inside!" Bucky slowly turned to face him and Steve stumbled to a halt.

That wasn't Bucky looking out from those eyes. Lightning split the air, turned the scene blinding white, the metal of his arm gleamed, the plates shifting, realigning.

He flashed back to the boat. To the man standing among the bodies.

Rain pounded down and Steve slowly backed away. One step, two, and those eyes that weren't Bucky's tracked the movement. Bucky was gone, submerged as surely as if he'd been pulled under a storm-swollen wave. Steve would never make it back to the water and on land, this man who wasn't Bucky could kill him in seconds.

Unless...

Steve didn't want to. He didn't want to, it felt _wrong_ , but he didn't see another way out, not for either of them.

Son of a siren, he opened himself, let his power flow, found Bucky's heart's desire, muted and distant— _free,_ _I want to be free. No more Soldier. No more—_ and sang, power and temptation and promise, inescapable, irresistible. _I promise_ , his song whispered. _You'll be free. You'll be you. No more Soldier, only yourself._

It found Bucky and caught him, called him, and he stumbled forward, moving blindly until he thumped into Steve. Pressed into him, like he was trying to climb inside.

Gradually Steve let the song fade. He was shivering from the cold, from the power, from what he'd done to Bucky, and he waited, watching Bucky's face, watching his eyes.

"Steve?" It was a whisper, barely audible above the storm.

Steve sagged with relief, couldn't suppress a whole body shiver. "Bucky."

"You called me."

"I did."

"How..." Bucky stopped as Steve shivered again and he seemed to realise Steve was naked, wet, cold. "Hell, you're gonna freeze to death." He wrapped his hands around Steve's shoulders and pulled him inside the shelter. It was dark, but Bucky let go long enough to light a candle, then tossed the blanket around his shoulders and started rubbing his arms. "I'm sorry."

"There's nothing to be sorry for."

"Yeah, I'm damn sure that's not right. Hang on." Bucky stripped out of his wet clothes, dropped them in the corner, then pulled on dry ones. "Right, come here, will you?" He pulled Steve into his arms and Steve briefly thought about trying to pull away, but Bucky was warm and Steve was freezing and he was _Bucky_ again. "There you go," Bucky said as Steve slowly stopped shivering. "Let me get you a shirt or something. If you're staying?"

"I'm not leaving you after that." Bucky searched his face then ducked his head. Steve instantly missed the warmth when Bucky let go and held out a t-shirt. Steve traded him the blanket and pulled it on. Big enough for Bucky, it hung down almost to his knees.

Bucky sat down on the pallet with a sigh, then patted the spot next to him and Steve sank down to sit. He wrapped the blanket around Steve's shoulders and tentatively left his arm around him. Steve, still cold and unsettled, shivered once with the lingering aftershock of adrenaline, and leaned into his side. "Warm enough?" Bucky asked.

"Getting there." It was warm, curled against Bucky's side, and he kept rubbing Steve's arm, making slow circles.

"You called me back." 

Steve twined his fingers together. "Son of a siren, remember? Whoever you were, you weren't Bucky. Whoever you were—the Soldier?" Bucky gave a short, sharp nod. "He didn't have desires, but you do. Bucky does. I read your heart's desire and called to you. Just like the night I found you." Steve's smile was a little bitter, a little apologetic, and his voice was low as he said, "No human can resist a siren's song."

A long silence passed between them, filled by the sound of the storm, and then Bucky spoke, his voice careful, like a man picking his way across uncertain footing: "Will you always do that?"

Guilt swamped Steve and he sat up, pulling out from under Bucky's arm. "No, Bucky, I swear. I'll never use my power on you again. I'm sorry I did tonight," he said miserably. "I didn't know what else to do."

"No, Steve. That's not what I meant." Bucky's hand was very gentle when he touched Steve's. "I mean I _want_ you to use it on me."

Steve searched his face, brow furrowed in confusion. "I don't understand."

"I'm asking if you'll do that for me. If you'll keep on reading my heart's desires, make sure they're something safe. Not something bad. Something dangerous."

"I...could if you really want me to, but Bucky, what you're asking. That's a big thing you want me to do, that you want me to know. I have to ask why."

"Because someday what I want might be dangerous. And I'm going to have to ask you to stop me if it is. Would you do that for me? Sing me down if suddenly my heart's desire is something bad?"

"Bucky..." Steve didn't know what to do, didn't know what to say. The candlelight painted flickering shadows across Bucky's face, turning something that had become so familiar into something new, something strange. Something he couldn't read.

"Because you have to understand, I don't know everything that's in here with me. I don't know everything they did to me and what I know is enough to know I need some kind of safety." The corner of his mouth quirked up. "A warning siren."

Steve stared at him, then sighed, but some of his tension eased. Bucky could joke, could reach past whatever was so bad he was asking Steve to do what should be unthinkable. The hard knot of worry that he'd refused to let be panic started to uncurl. "I should drown you for that," he said gently, teasing, with a fleeting brush of his fingers across the back of Bucky's hand.

"But you won't."

"No, I won't. I'd never." He waited, letting the silence flow between them before he carefully asked, "Bucky? What did they do to you?"

For a long time, he didn't think Bucky would answer, and his voice was low, almost unrecognisable when he finally did. "I won't tell you the details."

"You don't have to tell me anything." He shifted sideways, so he was facing Bucky, closer but not quite touching, trying to say _I'm here, you're not alone._

"I think I do. I think I need to. I think you need to know." Steve stayed silent while Bucky spoke, while he said, "They tried to erase me, to replace me with the Soldier. Mostly succeeded, too, since I don't remember much about me. I know I used to be someone else, all I've got left of him is Bucky." He glanced at Steve and away. "I got that back the first time you called me, but I don't know where they got me or why they took _me_. I'm pretty sure I kept fighting them. I think I kept fighting. That's why they hurt me so much."

Steve caught the flash of rage before it escaped, kept his body loose, his expression calm. Bucky didn't need his anger; he needed Steve to _listen_.

A small smile, sad and a little lost, crossed Bucky's face. "Even when you fight with everything you've got you can still lose. And I lost, Steve. I killed for them. I killed so many people. Not just killed. I hurt people, I tortured them, I—" His mouth snapped shut so hard his teeth smacked together and he shook his head. "No details. You saw enough the night you took me. I became their Soldier, and I was perfect, I wanted to please them. I—"

"Not you, Bucky." Bucky looked at him. "I know that much. Whoever the Soldier was, that person—"

"Not sure person's the right word. Not sure _was_ is the right word, either."

"Whoever, whatever he was, he is, he wasn't, he isn't, you."

Bucky's eyes flicked over his face, doubtful and disbelieving, and Steve leaned forward, wrapped his hands around Bucky's knee and squeezed, as hard as his thin fingers, his skinny arms, would let him. "I know, Bucky. _I know._ I found _you,_ I called _you_ , from underneath him. You, _Bucky,_ not anyone else. The Soldier doesn't have a heart's desire, but you do. I read it, I called you, and you came, because you're Bucky, you're not the Soldier. You're not the same. You're not him."

Bucky let out a long slow breath and placed his hands over Steve's, gentle and careful with his metal fingers. "They still used me to kill. Used my body, used my mind. My hands, my eyes. You might have called me out from under him, but I don't know everything that's left behind. That's why I'm asking: will you keep checking? Make sure what I want most in the world isn't suddenly world domination, or perfect order, or a killing spree, or anything to do with—" He stopped, going a little pale.

"Bucky?"

"Or anything to do with HYDRA. They're the ones who had me. Who made me like this. Who gave me the arm, who created the Soldier."

 _HYDRA._ Steve would remember the name. He would remember all of this.

And if he ever encountered them, ever found the ones who had done this to Bucky, he would remember what a siren's song was meant for. He would remember that he was his mother's son.

"Yes, Bucky. If that's what you want, of course." It would be no small thing, to read the heart's desire of a human over and over again, and the temptation to open his mouth and sing would always be there, but this wasn't just a human. This was Bucky. For Bucky, he would do it. Weighed against Bucky's need to feel safe, this would actually be the very smallest of things.

For several minutes, Bucky didn't speak, just looked at Steve, long enough Steve started to worry he'd done something, said something, wrong, then his eyes softened. "Thank you. I can't tell you," he shook his head once, then slipped his arms around Steve's shoulders and pulled him close, "thank you." 

 

  ***   *   ***

 

The storm spent its fury and passed, leaving behind a gentle rain to soothe the island. Steve was curled on the pallet, fast asleep. It was the first time Bucky had ever seen him asleep outside of the water. He looked so different, asleep on land. So small, so helpless. He _wasn't_ helpless, Bucky knew, but he _was_ different.

Bucky knew he still didn't like being on land all that much, had figured out he didn't like the change in his body, how much smaller it made him, yet here he was, sound asleep next to Bucky, the top of his head pressed against Bucky's thigh.

He couldn't resist brushing his fingers through the fluffy hair at the nape of Steve's neck. Steve barely stirred, just shifted closer, fingers flexing a little, and Bucky couldn't help a tiny smile. Even in this shape, there were hints of Steve's strength that was so obvious in the water. The curve of his jaw, the way he held himself. The fact that he'd chosen to trust Bucky enough to fall asleep beside him, especially after he'd come face to face with the Soldier.

Bucky leaned back, tipped his head to rest against the rocky wall of the shelter, and stared at the guttering candle. He should have blown it out when Steve had fallen asleep—they only had so many—but he hadn't wanted to sit in the dark and he'd known he wouldn't sleep.

The storm had been bad, but he'd promised Steve he'd be fine. He'd thought he'd be fine, but in the middle of the lightning, the thunder crashing overhead, he'd felt himself fall, the ground dropping out from underneath him, sinking under the Soldier. Something in the storm had sent Bucky plummeting away into the depths of the earth and called the Soldier back to stand in his place.

He'd tried, scrabbling at the edges of his mind, but nothing he'd done could stop it. His last thought had been that at least Steve was safe in the water. Even the Soldier wouldn't be a match for him there.

Except he'd come back, wrapped in golden threads of light, to find himself looming over Steve, tiny and shivering in the cold. Steve, who'd found him again. Who'd sung to him and called him free.

Bucky knew he should probably be afraid. Steve's song could take him over, just as surely as HYDRA ever had. It could do what HYDRA'd never managed: catch _Bucky_ , catch him and lure him and hold him. He was defenceless against it. Helpless.

But he wasn't afraid, couldn't be afraid. Steve's song was golden and warm. Knowing Steve could do that, it made him feel safe. Knowing Steve was willing to read his heart's desire made him feel grounded. Like he could take the chance and trust himself, because he knew Steve would be watching. If some HYDRA programming buried deep in his brain suddenly decided to take over, Steve would see it. Steve would stop it. Steve would find him and call him back.

With a tiny sigh Steve shifted, curling closer, and Bucky tucked the blanket more securely around him.

By any rational standards, this was insane. A merman who was the son of a siren had stolen him free of HYDRA and brought him to a deserted island. A merman with a long, glorious tail and shimmering scales who in the ocean was bigger and stronger than Bucky, who on land was smaller and weaker but far from helpless, and in either shape his song could wrap Bucky in a golden web of his own heart's desire.

None of it could be real. How could it be real?

But Bucky had been mind-wiped and tortured and frozen over and over by a decades-spanning cult that wanted to subjugate the world and he barely remembered who he was.

In a world that was objectively insane, Steve was the only thing that made sense.

 

* * *

 

The next night, Steve didn't go to the water to sleep. He curled on the pallet next to Bucky, tucked up against his side. They didn't discuss it, Bucky didn't ask him and Steve didn't offer, he simply lay down and Bucky folded the blanket over him.

It was good to have him there. Bucky fell asleep wondering if he should move his pallet down to the cove.

He was still wondering when he stepped onto the train. It was cold and he shivered as he looked down at himself. He knew he was dreaming when he saw both his hands were normal under the deep blue sleeves of his long coat.

Snowy mountains swept by the speeding train.

 _Flash_. Gunfire and he was pinned down. It didn't feel like a dream. It felt real. He reached for weapons to return fire but came up empty handed. They were gone. They'd been taken. His arm was gone. Neither metal nor flesh. Just an empty stump, blood in an endless, ceaseless drip marking his path as he stumbled down the train.

As he ran past the open door.

Mountains. Snow. Faces looking down at him.

And he was falling. Reaching to catch himself but he had no arm.

Voices screaming. _Barnes. Sarge. Fuck no. Grab 'im._

Falling, the train spiralling into whiteness but there was no end. No ground. Just endless terror as he fell and fell and fell.

_Bucky._

Hands reaching for him, screaming his name.

_Bucky, wake up._

Fingers, hot as brands, touching him. His name. He came up out it with a gasp, his hand wrapped tight around a delicate wrist, clutching it desperately.

"Bucky," the voice soothed. _Steve._ "You're safe. You're safe."

"I was falling." Steve was only a shadow but his wrist was warm in Bucky's hand. "When I close my eyes I'm falling. I don't want to fall again. Please don't let me fall."

"Come with me." Steve shifted his hand as he stood, until he was holding Bucky's, and gently pulled. Bucky obediently rose to his feet, careful not to put any weight on him. In the water, Steve was stronger than him. In the water, Steve could tear him apart. Here on land a moment's carelessness and Bucky's strength could hurt him.

Steve led him to the water and he followed unquestioningly, pausing long enough to watch Steve strip out of his shirt. The moon was high and the stars were bright in the cloudless sky, making Steve's pale skin glow. Even this body, slight and skinny as it was, had a strange beauty. "Come in the water with me," Steve said and Bucky hurriedly kicked off his pants and followed.

Watching Steve change was always fascinating, his tail unfurling, muscles rippling like waves across his body as he moved in the water, the thin pink slits of his gills fluttering into place. He reached out a hand and drew Bucky further out, into deep water, too deep to stand. "On your back."

Bucky obeyed.

He floated on his back, watching the stars, countless pinpricks of light writing stories across the sky, Steve a silhouette by his side. He could feel the warmth of him, the occasional brush of Steve's tail against his legs. "You can't fall here," Steve said quietly. "It's impossible.

Steve was right. Slowly, his eyelids grew heavy. He wrestled them open, but they fought back. "Bucky. Sleep." Steve's arms were under him, his cheek was pressed against Steve's chest. "I've got you. You're safe."

 _Safe_. He could hear Steve's heart beating and the sound, the gentle movement of the waves, lulled him to sleep.

He woke in the morning curled on the beach, the blanket draped over his torso, the waves licking at his toes. Steve was sitting beside him. He turned to look at him and Steve said, "I couldn't get you any farther."

"Steve?"

"Yeah, Bucky?"

"I remember why I was falling. I remember who I was before I fell. I remember," the door in his mind had opened completely, warm light pouring through, illuminating shadows where truth had been hiding, "I remember so much." 

Behind the door was a path and while he'd slept Bucky had followed it to a garden filled with golden flowers, where the bees had hummed to him in a language he could understand.

They'd told him his name.

They'd told him where he'd come from.

They'd told him where HYDRA had found him.

"I was a Sergeant in World War Two. Sergeant James Buchanan Barnes." At Steve's blank look, he laughed and sat up, reaching to touch Steve, needing to touch him. "None of that means anything to you, does it?"

"Not really, Bucky, I'm sorry."

"Nothing to be sorry for. There's no reason why it should."

They sat together on the beach, leaning into each other, as Bucky explained. As he explained to a creature who'd never been human about a human war. Told him what he remembered about being captured the first time, about the experiments, about the one who'd done them.

"And then I fell off a train when my unit was capturing him, and they found me in the snow, gave me to HYDRA, gave me to him. I survived, I must have survived, because of what he did to me the first time. I can remember, he gave me this," he rolled his metal fingers, "said it would make me the fist of HYDRA." He snorted. " _Fist of HYDRA._ It's not even a good joke. Joke's on me, I guess, since that's what happened." Steve's hands were tight on his right arm and Bucky touched his cheek. "Steve?"

Steve blinked, seemed to shake himself, and focused on him.

"That's not all I remember. I remember bein' a kid, I remember I had a family," Bucky said softly, letting his hand fall. "I don't, I can't remember _them_ , I don't have their names, but I can see their faces, a mom and a dad and I think I had a sister. I remember they loved me," he said softly. "I remember I loved them."  

Slowly, Steve relaxed. "You had a family?"

Bucky nodded. "They're like a warm spot," he pressed one finger over Steve's heart, "right here."

Steve stared down at his finger, then looked up, hair falling over his forehead. " _James Buchanan Barnes_ ," he half-hummed and his name, his _name,_ in Steve's voice, almost a song, sent a shiver spiralling down his spine. 

"Bucky," he said, suddenly hoarse, and he cleared his throat. "I'm still Bucky."

"Bucky," Steve said, eyes warm. "You got yourself back."

"Not all of me, but," his smile was a bit shaky, because there was too much inside where before there'd been nothing... No, not nothing, he realised, there'd been _Steve_ , "but I did." He tipped his head, temple resting against Steve's. "Thank you."

"Bucky. You're the one who did it, who found yourself again."

"Maybe, but without you there wouldn't be a me to remember."

 

* * *

 

Bucky was filled with a strange tranquillity. The memories were settling into place, slotting themselves into the empty spots in his mind. Some of them weren't what any normal person would describe as good, but even those ones were still _his._ Still _him._ Pieces of Bucky he'd never had before.

Most days he'd spend in the water with Steve, sometimes swimming, sometimes floating, sometimes sitting in the shallows just to be with him, Steve's tail curling over his legs, Bucky's fingers brushing across the trailing fins that ran up its length. They'd talk, Bucky sharing his memories, explaining them to Steve, or sit in silence, watching the waves or the sky or the clouds.

It was like they were the only two people in the world.

Bucky should have known it couldn't last.

They were out beyond the cove when the drone of a motor smashed through the island's peace. Steve instantly dragged Bucky farther out into deeper water. Bucky didn’t try and fight him, eyes fixed on the small boat, long and sharp, beaching itself on the sand.

Two men dressed in black jumped out, Bucky's enhanced sight picking out weapons, one holding a device that he frowned at. Shook it, smacked its side. In the far distance, he could see the silhouette of a larger boat, which must have been where the smaller boat and the two men had come from.

Their voices carried over the waves and Bucky went rigid in Steve's arms. "I _still_ think he got eaten by a shark. They eat car bumpers, they wouldn't notice a metal arm."

The one holding the device replied, "Then why is the tracker picking it up?"

"Maybe the shark ate everything _but_ the arm and it washed up here?"

"Then we'll find the arm and take it back."

"And if this is another false positive?"

"Then we. Keep. Looking." The words held a distinct air of menace, audible even at this distance, and the second man didn't answer.

"It's HYDRA." Bucky was naked, weaponless except for the arm, and HYDRA had come for him. The arm. They were tracking the arm. They were going to find him.

Steve's arms tightened and he went cold. They were going to find _Steve_. Fuck, the things HYDRA would do to Steve.

"Steve." He turned in Steve's arms, grabbed his shoulders. "Go. You have to go. Now. Leave me here and go, swim as far and as fast as you can." He knew he was squeezing too hard, was going to leave bruises, but Steve had to listen. " _Now_. They're going to find me, they're tracking my arm, and you need to _go_. You can't let them catch you. You can't. I can't—" His voice broke and he shook his head, vicious denial, and shoved himself away from Steve.

 _Tried_ _to_ , but Steve's arms were an inescapable vice.

"No."

"Let me go, you have to let me g—"

" _No_." There was no more give in Steve's voice than there was in his arms. "No. They will _not_ take you. I sang you a promise and I will not break it." He started to swim, silent and swift, and Bucky struggled but he couldn't escape Steve. Not in the water. "I'm taking you to the cave and then I'll deal with them."

"You don't understand what they'll do to you." He was pleading. "They'll, god, they'll torture you, they'll brainwash you, they'll, I don't even _know_ how bad it would get, but you'll never get free, they'd never let you go."

"You know what they'd do to me because they did those things to you."

"Yes, so _I know what I'm talking about_ and I'm human. _You_ _can't exist_. If they get their hands on you..." He shuddered and kept pushing against Steve's chest, knowing it was futile but he had to try.

 

  ***   *   ***

 

Bucky was trying to get free of him and it was wrong to keep holding him against his will, but it was less wrong than the alternative.

Steve would not let Bucky trade his freedom for Steve's. They would not take him. No one was going to take him. No one was going to touch him. He held Bucky more firmly and his struggles were becoming half-hearted as Steve moved swiftly through the water. "Hold your breath." Bucky did and Steve swam through the tunnels, came up in the cave. "Stay here. I'll be back once it's safe."

"Steve, for fuck's sake, will you listen to me? They're armed, they have guns, they're going to _shoot you._ "

"Bucky." Steve's smile wasn't human. It wasn't even a smile. It was teeth and menace, something that would have been at home on a shark, and his eyes were dark and cold. "You're forgetting what I am."

"Steve?" Bucky went still and his voice was soft.

" _Siren's son._ This is what a siren's song was made for. I told you a siren can lure a shipload of humans. I told you no human can resist a siren's song. When I sang to you I set you free, but that's not what a siren's song is for. It's for destruction. It's for death. It's what my mother's blood means." He pressed his hand over Bucky's heart, feeling it beat against his fingertips. "I'm going to sing them into the ocean and kill them. That way they can never hurt you. They can never take you back."

Something faded into Bucky's eyes, a ghost of the man Steve had seen on the boat, in the storm, the man who wasn't Bucky, as he said, "We can get my uniform, my weapons, and I can do my own killing."

Steve pressed his hand harder against Bucky's chest "No. This way they never see you. This way they just disappear. Once they're dead I can take the boat far away and sink it." Bucky didn't speak, eyes locked on Steve's. "I stole you and I promised I'd keep you free. I stole you and I promised you'd never have to kill. Let me keep my promises."

Slowly, the ghost drifted out of Bucky's eyes and he nodded once. Steve turned to go, but Bucky's hand on his tail stopped him. His fingers were gentle, stroking over his fins. "Be careful."

He curled his tail around Bucky's legs, then swam away.

The small boat was half dragged up onto the beach and Steve smashed his tail against the side, drawing the enemy down into earshot.

Their heart's desires were greasy, dark, and shared between them: HYDRA's victory, all wrapped around with a longing for death and violence, to rise high by crushing people down.

He was a siren's son; he would sing them their heart's desire and lead them to their doom.

He lifted his voice and caught them. There was no guilt, just disgust at their hearts' desires curling inside him, at the promises he made as he sang to them: victory to HYDRA, the world at their feet, all the death and violence they desired. The two men, weighed down with heavy gear and weapons and solid boots, splashed blindly into the water after him, following desperately as he led them into deeper water.

They never even tried to swim.

Eyes wide and mouths gaping they followed his siren song. Delicate silvery bubbles drifted in a stream to the water's surface as they drowned, bodies slowly sinking towards the ocean floor.

Steve caught both corpses and impatiently dragged them deeper, weighed them down with stones to keep them there.

They would never hurt Bucky. Never threaten him. But they were only two and there were the rest still to be dealt with.

Steve stayed deep, swam further out, looking up through the water at the bottom of the larger boat; it was larger, but not _too_ big. There was a limit to how many humans it could hold.

Restless and angry, he circled beneath it.

In this moment he was his mother's son.

Steve reached out and one by one he read their hearts' desires. They filled him, swirled around inside him like an oil slick, like rotting flesh, until he wanted to flee. Wanted to stop. But he kept reaching, like plucking strings on a harp, felt himself stretching, growing taut as he added each one, and they were all the same: HYDRA's victory; violence, death, destruction; power; elimination of those who were a threat, who opposed them, who questioned them.

Until the last.

The last nearly broke him, brought a flash of rage so hot he nearly lost them all, because the heart's desire of the last was Bucky. Bucky helpless and in pain, and images of what he wanted to do to Bucky, _would_ do to Bucky if he ever got Bucky in his control, flowed into Steve.

Steve tipped his head back and sang, spat the words into the sky, promising everything and caught them all, called them into the ocean.

They came, tumbling over the side of the boat and into the water, falling down under the waves to drown, eyes wide, breathing in lungsful of cold ocean water, going under without a fight.

Except the last.

The last Steve grabbed by the scruff of the neck, held him above the water as he sang. For the last he kept singing until all the rest were dead, bodies drifting towards the ocean floor. For the last he let his song fade, then sank his fingers through flesh to hook under bone and tore him apart.

The wash of blood in the water was soothing, because no one with a heart's desire to hurt Bucky like that deserved to die in any way but screaming.

Dead or not, their desires had burrowed inside of him. He could see them, painted in his mind. It was like his heart had been dipped in slime, his mind coated in it. He shuddered once and returned to Bucky.

When he surfaced in the cave he didn't see Bucky and his heart seized. Had there been more? Had there been some he missed? Had they come for Bucky while he'd been dealing with the rest? Steve didn't call out, just slipped silently through the water, and then Bucky emerged from the darkened shadows in the depths of the cave.

"Bucky," he breathed, rising higher above the water's surface and swimming for the shallows.

 

***   *   ***

 

Bucky wasn't sure how much time had passed since Steve had disappeared under the water. He'd let himself sink into that cold place, not the Soldier, not that far down, but far enough he could set the fear for Steve aside, far enough he could set the guilt aside, and wait.

Wait for Steve to return, _It's for destruction. It's for death. It's what my mother's blood means. I'm going to sing them into the ocean and kill them_ , repeating over and over in his mind like a mantra.

He could still feel Steve's fingers against his chest.

Steve had gone out to kill for him.

Bucky had let him.

His heart seized, stopped, slammed into high gear when Steve reappeared, and he threw himself into the water with a splash, dropped to his knees, hands moving over Steve, down his arms, his chest, across his back, sliding down his tail. Checking him for injuries.

"I'm not hurt." Steve caught Bucky's hands. "They didn't touch me and they're dead now."

"You're sure?"

"I watched them drown." Steve's fingers flexed, tensing and releasing. "I watched them die."

"No," he shook his head impatiently, "you're sure you're not hurt?"

"I promise, Bucky. I'm not hurt."

Bucky's eyes travelled over Steve. His tail was lifeless, the fins lying limp, and Steve gently pulled his hands away and folded them against his stomach, like he didn't want to risk touching anything. Like he didn't want to risk touching Bucky.

Guilt flared. "I'm sorry you had to kill. I shouldn't have—"

"No, Bucky," Steve said quickly, firmly. "It doesn't bother me. I'll kill whoever I have to to keep you safe."

He couldn't doubt him, not with that tone, but he knew something was wrong. He reached out to rest a hand on Steve's shoulder and when he shied away, didn't let Bucky touch him, avoided his eyes, he understood. God, he should have realised right off. "Steve?"

Steve didn't look up.

"Steve," he said gently, "look at me?"

Finally he glanced up and Bucky said, "It was their hearts' desires, wasn't it? They were...bad."

Steve flinched and Bucky slipped his arm around Steve's shoulder, ignoring the way he tried to pull away. Slowly, Steve leaned into him. "They were like slime. And one of them—" Steve shuddered. "No. No, you don't need to know that."

He didn't know what to do, he didn't know how to make it better, because he could imagine what the heart's desire of a HYDRA operative would be... Except suddenly he did know. The answer was obvious. "Sing to me." At Steve's confused look, he clarified, "A siren song. Sing to me. To wipe them away. You did that for me, took them inside of you for me, let me do this for you."

"I'm not going to sing to you."

"I don't know what my heart's desire is, but you do and it's got to be better than HYDRA's, right?" Steve was slowly shaking his head. "Please. I know what I'm asking, I know you won't hurt me, I know you'll let me go. I want you to."

He got an idea of just how bad what was swirling around inside Steve must be when he asked in a small voice, "Are you sure?"

"So sure, Steve. Sing to me."

For long moments Steve searched his face and Bucky gazed back fearlessly until he saw Steve open his mouth, saw him tip his head back, and then there was nothing but a song, golden and warm, promising him freedom, promising him HYDRA would never have him, never hurt him. He was submerged in it, was drowning in it, but it was warm and safe, it wrapped around him, drew him forward, and he was gone.

He came up out of it in Steve's arms, Steve's tail curled around his legs, breathing into Steve's shoulder. He couldn’t speak, just made a soft, small noise.

Steve's fingers brushed through his hair. "Are you with me?" he murmured.

He nodded, but there were no words. _Steve always keeps his promises._ After a minute, he managed to say it, say, "You keep them."

"Bucky?" He could hear confusion, concern.

"Your promises. The song, what you promise me in the song." The golden light was starting to fade, he could think again. "You always keep them."

There was a smile in Steve's voice as he said, "I'll always try to."

He managed to sit up, Steve's strong hands supporting him. "Do you feel better?"

"Yeah." Steve eased away from him, tail uncurling from his legs, and Bucky felt it like a loss. "Lighter, like I've only got you in here." He touched his chest. "Thank you. I know it can't feel great when I do that."

"No." He met Steve's eyes. "No, it's good. It feels good. Like being wrapped in you, like being completely safe. I know you said it's supposed to be for death and destruction, but when you sing to me it's...it feels good."

"Really?"

"Really. I'd never lie to you, Steve, especially not about something like that." Steve looked stunned, but his tail curved over Bucky's ankle, the soft fins on the end settling against his skin. "We'd better get out to the boat. There's thing I'm going to want, things I need to see."

 

***   *   ***

 

Bucky's heart's desire had been bright and clean and pure, clear water washing away the HYDRA stink, the horror of those images of Bucky in a way Steve would _never_ see him.

It had poured through him as Bucky fell into his arms, as he'd curled his tail around Bucky's legs. He'd been mute once he let his song fade, incapable of speech in the face of Bucky's trust. Steve had proved he was his mother's son, turned his song to its true purpose: death and destruction, the corpses of the men who'd come for Bucky littering the ocean floor. But still Bucky had trusted him, trusted his song, asked Steve to sing to him, to clear away HYDRA's darkness.

Steve had been incapable of _thought_ in the face of Bucky saying he _liked_ it, that it felt good, that it made him feel _safe_. It was a gift he could never repay.

He stayed silent as they made their way to HYDRA's boat, Bucky in the small boat, Steve towing it rather than wasting fuel. The closer they got, the more Bucky changed. He was still Bucky, but he was different. More dangerous. He looked like a predator.

The boat was empty of life, but Bucky was still careful and cautious as he boarded. "Traps," he explained to Steve. "Security systems. You stay in the water for now." He disappeared from sight and Steve craned every one of his senses, alert for danger.

He returned carrying a gun, carrying gear Steve didn't recognise. "There's a lot we can salvage, a lot that's going to be useful. Food, clothes, weapons. I'm going to start bringing stuff up, start loading the boat." He crouched, resting the gun across his thigh. "Do you want to come on board?"

"Do you need me?"

Bucky looked torn. "I don't need you to carry gear or help me choose what to salvage."

"But you do need me."

"Yeah, yeah I do."

"Pull me up." Steve held up his arms and changed, legs for tail, size and strength for smallness and vulnerability, except he didn't really feel like that when he was with Bucky. It was like Bucky was his missing strength. His missing ocean. "But I'm not going to have any clothes." Bucky was dressed, they'd stopped long enough for him to run up to the shelter, but they hadn't brought anything for Steve.

Bucky did a double take, then laughed. "Steve, I don't even notice anymore. Mostly I worry that you're gonna get cold." He set everything on the deck then reached down, careful with his metal fingers as he wrapped his hands around Steve's ribs and lifted him easily, setting him on dripping wet feet on the boat's deck. "Do you want my shirt?"

"No, I'm fine." He stayed by Bucky's side as he methodically worked through the boat, Bucky making piles of things as they went.

They found a duplicate of the tracking device the HYDRA operative had been using on the island, the device that was now deep at the bottom of the ocean. Bucky turned it on and it started flickering wildly. His face was blank, eyes hard, and Steve gently touched his back. "It'll have to come out," Bucky said. "It'll have to come out or they'll always be able to find me. I'll never be safe."

"So we figure out how to do that." Steve had no idea, but he was confident Bucky would.

"Right." He took the tracking device, took tools, took things Steve didn't know the name of, took clothes and food and other human essentials, and they loaded the small boat. Bucky hauled up the anchor on the large boat and, while he piloted the little boat back to the island, Steve, returned to his proper form, hauled the large boat away, building up speed until they were flying over the waves.

When Steve was satisfied they were far enough away he dove under the hull and punched a hole in the bottom, tore at it, making it larger and larger until it began to fill with water.

He stayed, watching, until hours later it had sunk completely from sight.

When he finally returned to the island he was exhausted. It would have been easier to sleep in the cove, lulled to sleep by the movement of the ocean, the comfort of his home, but it wasn't what he wanted.

He hit the sand and changed shape, stumbled up to Bucky's shelter and dropped onto his pallet. Bucky pulled the blanket over him and rubbed his back and Steve fell asleep with Bucky's warmth radiating through him, Bucky's strong arm over his bony shoulders, knowing Bucky was safe.

 

* * *

 

The next morning under the bright sun Steve carefully angled one of the metal plates from Bucky's arm to reflect light _inside_ Bucky's arm. Bucky had gathered up the tracking device and the tool kit, a set of fine metal skewers and Steve, and they'd set up on the highest rock, as far away from any sand as possible. "I might need you to do this," Bucky murmured as he delicately prodded a wire.

"I don't know anything about," Steve nodded at the innards lying exposed, like the guts of an unknown fish, "that."

"But your hands are small, and I think you can reach it. The tracker has to come out." Bucky's brief smile was dark, would have done any shark proud. "Unless you know a way to get rid of it."

It took Steve a second to figure it out. "You want to get rid of your arm?" he asked, horrified.

"It was never mine. They gave it to me to kill. It's just another weapon, just like they made me into." He flexed the metal fingers, clenched them into a fist, and Steve saw the insides shift and twist.   

Steve rested his hand on the metal, warm from the sun. "It _was_ never yours. It is now. You never have to use it to kill. Never again. I promised that the first time I saw you."

Bucky was silent for a long time, watching Steve's hand. "You did," he finally said. "And you always keep your promises." He closed his metal fingers around Steve's wrist, not hard, not hurting, but it would be impossible for Steve to break his grip. "And you're not afraid of it, even when you're small like this."

There was something in Bucky's voice... Steve considered his words, watched Bucky's face. _It's just another weapon, just like they made me into._ "Do you mean am _I_ afraid of you when I'm small like this?"

Bucky looked up at him. "Maybe."

"No, Bucky. I'm not." Steve licked his lips, not sure how to explain. He was certain Bucky already knew this, but if he needed to hear it, Steve would find the words. "The ocean's where I belong but I sometimes liked to walk on land. I liked the way it felt, but I didn't like the way I felt. That's why I had the cave. No one was ever going to find me there. It was safe. When you first needed me on land, when I had to take this shape to help you, I didn't like it much. I wasn't afraid of you exactly, but I wasn't comfortable. I was happier when you came to me in the water."

"Where you were stronger than me."

"Where I was strong, but also because that's my true shape, tail and gills and size and all, and because that's my home. Now," he turned his hand and Bucky instantly let go; Steve slid his hand into Bucky's metal one and curled his fingers closed, "now I don't care. Being with you's like being with myself. On land, in the sea, there's no difference. So no, I'm not afraid of you."

There was a smile pulling at the corner of Bucky's mouth as he looked down at Steve's hand wrapped around his. "I guess if I tried to hurt you you could just sing me down anyway."

"If I was fast enough I could, but that's not why." Steve squeezed his hand. "I'm not scared of you because you're not someone to be scared of. To me, you're just Bucky. Out of the water you could hurt me if you wanted to, you're fast enough and strong enough, but I know you'd never want to."

Bucky tipped forward to rest his forehead on Steve's bony shoulder and Steve could feel him smiling. "You're right."

"Of course I am." He briefly rested his head against Bucky's then elbowed him. "Now show me what I have to do to get this thing out of you."

 

* * *

 

There was a lot of cursing and swearing, and the sun had moved across the sky, but eventually Steve pulled a tiny piece of dull metal and plastic out of Bucky's arm. He turned it over in his hands while Bucky put the plates back in place. "I could feed this to a shark," Steve said thoughtfully. "Put it inside a fish and they'd eat it, no problem. And sharks migrate."

Bucky frowned at him then started to laugh. "Yeah, okay. Let them have fun following a shark around." He finished fastening the plates, flexed his fingers, and nodded in satisfaction. "There's something else, though."

Steve looked expectantly at Bucky.

"I think." He set down his tools and looked at Steve seriously. "I think it's time to leave. Even if you feed the tracker to a shark, HYDRA could come back. If they decide to trace the boat's route they'll find the island eventually and I can't be here."

Steve briefly closed his eyes. "Of course." For one tiny, shameful moment something dark rose up in him, the urge to throw his head back and sing, to keep Bucky with him forever. _Siren's son_. He angrily shook it off. No. Never. _Never_. "Where do you want me to take you?"

"I don't know. I haven't figured that part out yet. Problem is everything needs money and that's the one thing I don't have much of."

Steve weighed it up. Even if Bucky was leaving him, even if he was going to lose him, there still wasn't anything he wouldn't do for him. "Do humans still value gold?"

Bucky quirked an eyebrow at him. "More than just about anything."

"Think you'll be okay for," he did some quick calculations, "for two, maybe three days on your own?"

"Should be. Even if they decide to trace the boat they're not gonna jump straight here. Why?"

"I'm going to solve your money problem so you can go where you need to."

"Steve?"

He closed his hand around the tracker and stood. "I'll be back as soon as I can." He ran up to the shelter to fetch the net bag and shed his loose shirt, Bucky staring after him in confusion, then down to the water and dove in, feeling his true shape form around him. He didn't look back.

Steve knew exactly where the shipwreck was but he still had to get there. On his way he caught a large fish, shoved the tracker inside, and fed it to a shark, who seemed surprised but not unhappy at the free meal.

The spot where the ship had gone down was deep and cold even for him and he was shivering when he came back up, but he had two gold bars in the net bag.

It was a slower swim back with the gold and the knowledge that he'd be giving Bucky what he needed to leave him.

 

* * *

 

Bucky kept watch for Steve. Something hadn't been quite right when he'd left, and he was impatient for him to come back. On the third afternoon Steve swam into the cove and Bucky trotted down to the beach to meet him.

"This is what you need, right?" Steve asked, tossing the net bag up onto the beach where it sank into the wet sand under the weight of two large gold bars.

Bucky's jaw dropped. "Steve, what? Where did you get these?" He pulled one out of the bag and his eyes went wide. "This must weigh at least ten pounds."

"There's a shipwreck, went down loaded with these and lots of other things humans seem to value. If this is enough, you can load up the boat tomorrow and I'll take you wherever you want to go."

Steve's voice was flat and his tail was lying limp in the water. "Steve?" Bucky said his name tentatively, setting the bar down in the sand. "I can't stay here. I would if I could, but it's not safe."

"I know, Bucky. I know. And I want you to be safe. That's all I want. I'm just," Steve's tail curled tightly, the fins rippling as a tremor passed down it, and Steve, sounding like he was about to shatter into pieces, said, "I'm going to miss you."

Bucky abruptly sat down, like his legs had been cut from under him, the waves swirling around his ankles. "Are you," he swallowed, "aren't you coming with me?"

"I'll take you where you need to go. You know that."

"No, I mean, aren't you coming _with_ me? I thought... No. I guess I shouldn't have. Of course you're not." It felt like something had just been ripped out of him. _Steve_. "Maybe I _could_ stay here."

"Bucky?" Sudden hope bloomed on Steve's face. "You want me to come with you?"

"Yes. Yes, Steve. Of course. I'm not leaving. Not without you."

Steve pulled himself out of the surf and wrapped one strong hand around Bucky's calf. "Really?"

He took a chance. "What's my heart's desire?"

Steve's eyes went dark and then he smiled, warm and filled with joy. " _Oh_. Together, not alone. Yes." He let his forehead fall to rest against Bucky's knee and Bucky ran his fingers through his wet hair. _Together. Not alone._

They sat together, just breathing, Steve's hand warm around his leg, Bucky's fingers curled in Steve's hair. "Where should we go?" he finally asked.

"Where do you want to go?"

"Somewhere they won't find us. I'm," Bucky glanced ruefully at his arm, "kind of distinctive.

"How come it's up to me?"

He could _hear_ Steve's grin and he tugged on his hair. "Because my knowledge of the world is places it's good to kill people, places I _have_ killed people, a few places from the nineteen forties and HYDRA bases. I'm thinking we’ll be better off if you come up with somewhere for us."

"I take your point." Steve hummed thoughtfully and it sent a frisson of warmth down Bucky's spine. It wasn't a siren's song, but it was still Steve's voice, which could reach inside of him with or without power. "What if we stay on the ocean?"

"What are you thinking?"

"Would the gold be enough to buy a boat?"

Slowly, Bucky smiled.

 

* * *

 

Bucky was certain the gold would be more than enough to buy a boat—by his estimate both bars weighed at least ten pounds; he was pretty sure they could buy whatever the hell they wanted—but first he'd need to turn them into cash.

He remembered a lot from his time with HYDRA. Usually, that was a curse. Sometimes, like when he needed to offload gold bars of uncertain provenance, it was a blessing.

His memory offered him the location of a number of shady people, not HYDRA affiliated, who would take the bars off his hands, no questions asked. The one Bucky had in mind wasn't on the coast. It would mean going inland, and he didn't like the way Steve went pale when Bucky explained. "You could stay in the ocean and wait for me," Bucky suggested.

"No." Steve was radiating stubbornness Bucky wasn't prepared to argue with. "No, I'm going with you. What if you don't come back?"

"Steve, I'm going to come back."

"What if something happens and you can't? I'd never know. I'd just be waiting for you and—" His mouth snapped shut and he shook his head. "I'm going with you."

They packed the boat. Bucky rigged a shade over it with branches and the blanket and rope, because it was going to take a few days, even at Steve's speed, to get where they were going and the sun on the ocean could be blinding. From what he'd salvaged from HYDRA and what Steve had stolen he put together proper clothes for Steve, to cover all of him, even if they didn't come close to fitting right.

Steve wasn't impressed, but he knew they were necessary, and Bucky packed them away in the boat.

What he'd salvaged from HYDRA gave Bucky clothes that fit well. Gave him proper boots. Gave him places to conceal weapons. Gave him what he needed to hide the arm. 

Steve towed the boat to conserve the fuel. When they were close to their destination, a coastal town where they could get a bus to the city holding Bucky's shady dealer, Steve pushed the boat up towards the rocks and Bucky leapt out, secured it, then offered a hand to Steve.

Steve made a face as he got dressed and when they were both as close to respectable as they were going to get they got into the boat and Bucky started the engine.

As they followed the coast, Bucky eyed Steve. "Looking a little green around the gills, there."

"I don't have any gills. That's the problem," Steve muttered.

Bucky gently squeezed his knee. "It's okay," he promised and steered the boat expertly through the waves. Apparently this was another thing he knew how to do. 

 

* * *

 

The city was huge. It was full of humans and cars and noise and too far from the ocean.

Steve hated it. He couldn’t even _smell_ the ocean anymore. He was wearing clothes that were too tight, that chafed his skin, and shoes on his feet that pinched. He hadn't minded the loose shirt he'd sometimes worn on the island but these were horrible. Bucky had chosen them when they'd stopped in the town on the coast, he knew they _fit_ , knew they were comfortable by human standards, but he hated them.

Even Bucky looked different here. Dangerous. Dressed in black salvaged from the HYDRA boat, his metal arm covered by long sleeves and a glove. His long wavy hair pulled back tight and sleek. Other humans drifted out of his way, sensing a predator, a shark in their water.

There were too many humans and the air was too dry, it stank of oil and heat and the too many humans. If not for Bucky's solid and unyielding presence at his side, he would have bolted back to the ocean.

"I'm going to get us a hotel," Bucky said. Steve barely heard him. He'd never felt so small but he _refused_ to feel helpless, refused to shiver as they turned into a crowded street and humans surged around them. His powers wouldn't even _begin_ to control this many people. Bucky's hand fell on his shoulder, pulling him closer. "Steve." It was soft, gentle, and he looked up at Bucky. "I'm not going to let anything happen to you. Okay?"

He nodded once. Took a deep breath. "I'm okay. It's all so..." He let his voice trail off and Bucky's lips pressed together.

"Come on." Bucky led him into a side street, and another, then down an alley and into a run-down looking building. He spoke to a man and then they were walking upstairs and into a room. With the door firmly shut, Steve felt a little better. When Bucky reached out and pulled him into a hug, he felt a lot better.

"Sorry," he said into Bucky's chest.

"Don't be stupid. This couldn't be any worse for you if it tried. You're doing great." That was a lie, Steve knew, but he'd take it. "How about you stay here while I go out and find my guy?"

Steve nodded, because he really didn't want to go back out into that. He would if he had to, if Bucky needed him to, but he'd much rather stay here where there was something approaching peace.

Once Bucky was gone, he poked around the room. Eventually he stripped off and sat in the shower, the spray falling over his head. Briefly he considered changing forms, but that could be dangerous. What if someone came in? What if someone saw him?

What if he got _stuck_ , considering the space in the shower wasn't that big.

Instead he just propped his chin on his knees and let the water wash over him. It wasn't the ocean, it wasn't even close, but it was comforting: no clothes rubbing, no shoes pinching, just cool water flowing over his skin.

He barely had time to react when he heard the door open and Bucky call his name before Bucky was on his knees next to the shower, reaching out to wrap his arms around him, saying, "I'm sorry, I shouldn't have left you," his shirt rapidly soaking through.

Steve patted his hair, his back. "I'm fine. Bucky, I'm fine."

Bucky sat back, eyes sharp, studying him, and Steve looked back, a little confused. "Are you sure?"

"I'm sure. I just wanted the water. It's nice. Comforting."

Bucky breathed a sigh of relief. "I saw you and figured you must have been doing worse than I thought." He shook his head. "Never mind. Hop out and I'll see if I can do better than a shower, okay?"

"Sure, Bucky." He stood, stepped out, and dried himself then stared at his clothes, nose wrinkling in disgust.

Bucky grinned and said, "Don't worry about them," before stripping out of his soaked shirt and offering Steve his hand. Steve took it and Bucky led him into the main room, sat down on the bed, pulled Steve to sit next to him, then wrapped him up tightly in his arms. Steve sighed and pressed into him. "Better?"

"Better." He felt safe, even so far from the water. Even in the midst of a city, with so many humans. Like Bucky was his ocean, like Bucky was his strength.

"Good." He rubbed Steve's back. "To make you feel even _better,_ I've got a pile of cash and a line on a boat."

 

* * *

 

It wasn't new, or big, or fancy, but it was solid, reliable, the perfect size for two people, a sailboat that had sailed around the world more than once, with a platform at the stern, just right for Steve. The guy selling it was happy to take cash in exchange for no questions and some quick lessons.

The moment they were away from the pier, out into the ocean and out of sight of land, Steve stripped off and leapt into the water, diving deep as he reshaped himself.

He was never doing that again. _Never._

Except he knew he would, knew if Bucky ever had to go back to land he'd go with him, even if nothing would ever make him like it.

He cautiously broke the surface, checking to make sure they were still alone, then swam up beside the boat, leaping over the waves left by the boat's passage. "Feel better?" Bucky asked.

"This is where I'm supposed to be."

"The ocean?"

"The ocean with you." He kicked water up with his tail, splashing Bucky, and Bucky grinned down at him.

"Once we get somewhere we can stop for the night, I'll come in and join you."

Steve grinned back and dove down, staying under the water as the hours passed. When the boat slowed, stopped, the anchor cutting through the water with a stream of silvery bubbles, he stealthily slid up under the stern platform, waiting, and when Bucky jumped into the water he grabbed him, pulling him down.

Bucky didn't fight him, just wriggled around, face alight with silent laughter, and Steve curled his tail around him and pushed up with powerful strokes of his arms until they broke the surface. "I think I missed it as much as you," Bucky said. "It's not the same being stuck on land."

"No, it's not the same at all."

With a boat, they could go anywhere. With a boat, Steve didn't have to leave the ocean. With a boat, Bucky would never have to stay in one place. He'd be safe, Steve could keep him safe. 

 

* * *

 

The third night on the boat, anchored in a sheltered bay, Bucky woke with the golden cocoon of Steve's siren song wrapped around him, his face buried in Steve's bare bony shoulder. He was warm, peaceful, drifting in a distant haze, but as he rose up through the light he realised with a start of surprise that his hand was empty.

He wasn't holding a gun.

Steve was humming in the back of his throat, simple music with no power behind it beyond that it was Steve. Bucky lifted his head. "Steve?"

"I got to you before you could sink too deep." Steve, naked and dripping wet, was staring up at him, concern in his eyes as Bucky stood on the deck of their boat with no gun in his hand. He'd been so sure he'd had a gun. "But you were slipping away. I was afraid you were going to disappear under the Soldier, so I called you."

"I was on the boat, the night you found me." Bucky flexed his fingers. "I was back there. I was doing it again. I killed them all again."

"It was just a dream." Steve wrapped his slim hands around Bucky's and the feeling of a gun in his hand faded. "You're here. You're safe. I stole you, remember?"

Bucky smiled, an echo of that golden light flowing through him. "I remember." He turned his hands to fold them around Steve's. "Thank you. For calling me, for not waiting."

A subtle tension left Steve's shoulders. "I didn't want to risk it."

"You did exactly right." He took a deep breath. "Would you stay with me tonight?"

"Of course."

With Steve tucked up next to him, one of Bucky's shirts hanging off his skinny frame, his back pressed against Bucky's side, Bucky drifted back to sleep.

Steve stayed that night and the next night and the night after. He kept almost every nightmare away and the ones that braved his presence didn't last, the warmth against his side reminding Bucky that they were just dreams.

 

* * *

 

Sleeping next to Bucky wasn't a hardship. Steve slept well curled against Bucky's side and Bucky slept better, breathed easier, had fewer nightmares with him there.

But he couldn’t stay every night. He needed to be back in the ocean, back in his proper body, even if he didn't really want to leave Bucky. "Bucky?" he said while they were eating dinner, sitting cross legged on the deck, side by side, knees touching.

"Yeah, Steve?"

"I need to spend tonight in the water."

Bucky shifted to look at him, sudden guilt on his face. "Why didn't you say something? You don't have to stay with me."

"I like staying with you," Steve said, smiling a little as he admitted it, watching Bucky's lips curve in an answering smile. "And I'm saying something now."

"I guess you are, huh?"

"The words, 'I need to spend tonight in the water' were kind of a giveaway."

Bucky rolled his eyes, then poked at a rough spot on the deck. "Could I come with you?"

Steve studied him, trying to work it out. "Bucky? What are you asking?"

"Could I sleep with you in the water?"

Steve stared at him in surprise. "Do you want me with you when you sleep that badly?"

"No, it's not that. It just might be nice, if there's any way to make it work. You stay with me up here on, I guess it's not dry land, but close enough. It'd be nice if I could go where you belong, in the water."

A rush of warmth shot through him and he had to stop himself from leaning into Bucky, from reaching over to take his hands. Bucky wanted to come and sleep with him in the ocean. That was...Steve didn't have the words for what that made him feel. He frowned a little, trying to work it out, and Bucky quickly said, "Or if it's a bad idea, just pretend I didn't say anything."

He gave in to the urge and wrapped his hands around Bucky's. "No, it's not bad, I'm just trying to think of a way to make it happen." He usually slept on the sea bed, and that wouldn’t work. "I think I've got an idea."

Night fell and Steve slipped into the water, tail unfurling as he took his proper shape. Bucky was watching from the platform at the stern of the boat, wearing a pair of swimming shorts.

Steve hooked his tail around the anchor chain and held out his arms. Bucky swam into them and Steve wrapped his arms around Bucky then lay back, bringing Bucky with him. Bucky's legs fell to either side of his tail as he let himself float, cradling Bucky against his chest. "If you get too cold, you have to let me know." 

"I will, but it's pretty warm and you give off a lot of heat." Bucky shifted, wriggling a little, getting more comfortable, and Steve rearranged his arms, holding him tightly. "This is kind of strange, huh?"

"Maybe a bit."

"But nice?"

"Yeah, Bucky, it is." He had the sudden urge to press a kiss to Bucky's temple and had to hold back a laugh at himself. "It's really nice."

"Told you."

"I'm glad I listened."

He was surprised when Bucky actually fell asleep. He hadn't expected that. He'd thought they'd float for a few hours and Bucky would give up and go back on board. Instead his heartbeat slowed, his breathing deepened, and then he was fast asleep, trusting Steve to keep him safe.

Steve pressed his nose against Bucky's hair and breathed in. "You're incredible," he murmured and let himself doze off.

If Bucky's breathing changed, if the currents changed, if anything changed, anything approached, he'd be instantly awake, but for now, he was going to bask in the peace of being where he belonged with Bucky where _he_ belonged.

 

* * *

 

A few nights later, nights that had alternated between Steve sleeping in Bucky's bunk and Bucky sleeping cradled in Steve's arms, they were on the platform at the stern of the boat watching the sunset. Bucky's legs were dangling in the water, Steve's elbows were resting on the edge of the platform, his tail curling idly back and forth in the gentle waves. It was quiet, both of them relaxed, and Steve reached out to read Bucky's heart's desire, keeping his promise.

It was nothing he'd seen before. Not freedom, not peace, not no more killing. Nothing to do with HYDRA or the Soldier.

It was Steve.

Bucky's heart's desire was _him._

Steve went still, stared up at Bucky, unblinking, unmoving, for long enough it caught Bucky's attention. He looked down at Steve, momentarily puzzled, then he blew out a long, uncertain breath. Steve carefully covered Bucky's right hand with his own, twining their fingers together. Bucky started to smile. "I guess trying to hide it from you was kind of stupid."

"Little bit, yeah."

"What do you think?"

"I think if you could read my heart's desire, we'd match."

Bucky slid into the water and Steve rested an arm on the platform next to him so he could wrap his tail around Bucky's legs. Bucky's eyes fluttered shut as Steve delicately traced the lines of his face, humming softly. "Sing to me?" he whispered as Steve nosed his cheek.

"Are you sure?"

Bucky opened his eyes and they were clear and deep. "You're my heart's desire. Sing me you. Promise me you."

Gently, quietly, lips against Bucky's temple, Steve sang a siren's song. Golden words, words of promise, words of truth, that wrapped around Bucky, warm and soft; inescapable, but Steve could no more break free than Bucky. _I promise you me._ _You'll always have me because I'll always have you._ _I love you._

_I love you._

Bucky was pliant and relaxed against Steve as the song faded. When he could speak he murmured, "I love you," fingers brushing the line where Steve's scales met skin, tracing up Steve's spine, a feather's touch outlining his gills, and cupped Steve's cheek. "I can't sing it to you, but I promise, too. I love you, too," he said and kissed Steve.

It took his breath away and he wrapped his arm around Bucky, tightened his tail, gently stroked Bucky's legs with his fins and felt a breath of laughter in the chest pressed to his. It was perfect and wonderful and his mouth moving over Bucky's, Bucky's mouth moving against his, was glorious. It was completely new, like nothing they'd ever had, and at the same time it was familiar, it was Bucky, Bucky's touch, Bucky's breath, _Bucky._ "Bucky," he murmured, and felt him smile.

"You sang me you." Bucky pressed a kiss to the corner of Steve's mouth, right hand curling around the nape of Steve's neck, fingers combing through the fluffy hair. "You promised me you."

Steve pulled himself closer, held Bucky as tightly as he could, curled his fins around Bucky's ankles. "Always and forever, Bucky."

Bucky gazed at him, eyes dancing, then kissed him, soft and sweet. "That might just be long enough."


End file.
